1. Field of the Invention
The present invention generally relates to the field of water quality monitoring devices. More particularly, the present invention relates to the field of water quality monitoring devices utilizing the remote electro-optical sensor (REOS) system.
2. Description of the Prior Art
The general acronym REOS (Remote Electro-Optical Sensor) refers to moored in-reservoir water quality monitoring systems. REOS systems provided the first continuous in-reservoir monitoring of nuisance phytoplankton populations in drinking water reservoirs. Prior to the development of REOS technology, laboratory inspection of reservoir water samples was needed to track algal population dynamics.
A prototype system (REOS-1) and a subsequent developmental system (REOS-2) were deployed by the Los Angeles Department of Water and Power (LADWP) in 1989 and 1992, respectively, as described in White, B. N., Kiefer, D. A., Morrow, J. H. and G. F. Stolarik (1991), Remote Biological Monitoring in an Open Finished-Water Reservoir, American Water Works Association Journal, 83:107-111.
REOS-1 and REOS-2 systems were designed specifically to monitor nuisance algal populations by making accurate measurements of the red fluoresced light, stimulated by ambient sunlight, which radiates from all eukaryotic (higher plant) phytoplankton during photosynthesis. Research primarily on marine phytoplankton has shown that the fluorescent flux can be related both to chlorophyll concentration and to instantaneous rates of photosynthesis.
The REOS-1 and REOS-2 systems utilized specialized instruments, including profiling natural fluorometers (PNF), to measure both photosynthetically active radiation (PAR) between 400-700 nm as well as the red fluorescence emitted from the phytoplankton crop. The fluorescence signal is measured directly as the upwelling (nadir) radiance over the relatively broad bandwidth of chlorophyll fluorescence. The measurement is different from chlorophyll fluorescence measured using a strobe fluorometer in that the fluorescence signal results from the same source as that driving photosynthesis in situ.
The prototype REOS-1 system used a single PNF to monitor the phytoplankton crop. Since the PNF measures upwelling radiance directly below the sensor and samples a volume approximately 5 meters below the instrument in clear waters, the developmental REOS-2 system incorporated additional PNF's to increase optical coverage of the water column. In addition to the optical measurements, the REOS-2 system measures pH, dissolved oxygen (DO), oxidation/reduction potential (ORP) and conductivity. The REOS-2 system also utilized a dedicated 80486-microprocessor based remote access workstation (RAW) to control the system, acquire the data from each instrument, and perform functions for remote telemetry of the data.
It is desirable to develop a fully automated REOS system utilizing multiple regions of the spectrum which records and reports the status of a wider variety of water quality variables in open drinking water reservoirs, and thereby provides reservoir managers with the means to detect and intercept impending phytoplankton blooms before taste, odor, and appearance problems arise and to optimize the algicidal treatments needed to maintain control of phytoplanktonic growth.